Conventionally, as a power conversion apparatus to drive a motor with a relatively large capacity, a three-level power conversion apparatus has been used which is provided with a three-level converter, and a three-level inverter to convert the direct current of this output into an alternating current. This three-level power conversion apparatus is configured to have three levels DC voltages composed of a positive electric potential, a negative electric potential, neutral point, and if a voltage (electric potential) of the neutral point fluctuates, the voltages of an AC power supply and the motor as a load of the power conversion apparatus also fluctuates, to cause unnecessary harmonics to be generated. For this reason, a proposal has been made, wherein positive side and negative side switching devices are provided which are respectively connected from a neutral point to a positive potential and a negative potential through a common reactor, and when a voltage imbalance occurs, the charge of one DC capacitor is transferred to the other by turning on-off the switching devices, to thereby suppress the variation in the neutral point potential (Refer to Patent Document 1, for example.).